Wear plate for the breech mechanism of guns



Oct. 14, 1952 5. J. FINN WEAR PLATE FOR THE BREECH MECHANISM OF GUNS Filed Nov. 30, 1944 2 SHEETS-SHEET 1 Oct. 14, 1952 s. .J. FINN 2,613,576

WEAR PLATE FOR THE BREECH MECHANISM OF GUNS Filed Nbv. 30, 1944 2 SHEETS-SHEET 2 In venfor Sadr-12y J z nn By izz JA izorney Patented Oct. 14, 1952 ATENT OFFICE WEAR PLATE FOR THE BREECH MECHA- NISM OF GUNS Sidney J .=Finn, Beverly, Mass., assignor to United Shoe Machinery Corporation, Flemington, N. 3., a corporation of New Jersey 7 v 7 Application November 30, 1944, Serial No. 565,876

8 Claims. (01. 89-24) This invention relates to breech mechanisms tionl For closing the breechblock a'heavy spring is employed which acts to rotate a crank shaft journaled in the breech ring and provided with a crank carrying block received in an upwardly and forwardly inclined T-shaped slot in the lower central portion ofthe breechblock. The crank shaft is provided with a crank arm which cooperates with a cam plate mounted on the gun carriage to rotate the crank shaft during the counter-recoil movement of the gun to move the breechblock downwardlyagainst the force of the heavy spring aforementioned.

Carried by the breech ring of the'gun at opposite sides of the breechblock is a pair of extractors having outwardly extending trunnions received in arcuate slots in the breech ring for supporting the extractors for rocking movements' The extractors have inwardly extending lugs received in cam slots'in opposite sides of the breechblock, the upper portions of which slots are inclined upwardly and forwardly so that during the final downward opening movement of the breechblock, the lower portions of the ex-' tractors are moved forwardly and the upper portions are rocked rearwardly to extract the empty shell case from the gun. The forward walls of the cam slots are slabbed off at their upper portions to form shoulders on which the inwardly extending lugs on the extractors rest when the breechblock is fully opened whereupon the extractors serve to lock the breechblock in open position at the conclusion of a firing operation.

Springs act on the extractors to hold them in looking positions. Upon the introduction of a new round into the gun the rim of the shell case engages the extractors to rock them in directions to move the lugs off the shoulders whereupon the heavy spring, acting on the camshaft, causes closure of the breechblock.

Breechblo'cks of guns of this type have con-' lugs of the extractors have moved oil the shoulders the initial closing movement of the breechblock is delayed for the short period of time necessary for the spring to overcome the inertia thereof. The lugs carried by the extractors in moving off the shoulders engage the rearward Walls of the cam slots which are quite steep and unless the round is rammed with sumcient force the engagement of the lugs with the'rearward walls of the cam slots will cause the round to be arrested in its forward movement momentarily until the breechblock starts to close. This closing movement of the breechblock moves the extractors into their proper positions but if the round has actually come to rest during this instant when the lugs on the extractors engage the rearward walls of the cam slot, the round may not be introduced sufficiently far into the gun to be engaged by the inclined wall of the breechblock and damage may result to the round. For this reason it is necessary that the round be introduced with sufficient speed to insure its continued movement. If the round is rammed sufficiently fast the lugs on leaving the shoulders engage the rearward walls of the cam slots with enough force to start the upward movement of the breechblock before the springs become eifective. Due to the fact that the upper portions of the cam slots are relatively steep, the blow exerted by the lugs on these walls is considerable and the reaction between the outwardly extending trunnions and the cam slots in the breech ring is also high. Consequently considerable wear takes place both on the lugs and in the rear walls of the cam slot and on the arcuate slots in the breech ring. This necessitates frequent replacement of the breech ring and the breechblock, particularly in guns of the type described if they are mechanically loaded at high speeds in which a very high ramming velocity is necessary to maintain a high firing rate of the guns.

It is an object of the present invention to overcome the excess wearing of the parts occasioned by the structure above described thus obviating parts which require accurate machining and are consequently quite expensive. To this end, and in accordance with a feature of the invention, provision is made for eliminating the blow between the lugs on the extractors and the rearward walls of the cam slots during the loading operation. This is accomplished in accordance with the illustrated embodiment of the invention by forming the rearward walls of the cam slots of movable, vertically-disposed plates pivoted near their central portions about horizontal axes. With the gun loadedand the breechblock closed, these plates are held by latches in operative positions so that the shape of the cam slots is similar to that'heretofore employed in guns of this type. Thus, following the firing operation and downward movement of thebreechblockduring counter-recoil of the gun, the cam slots act on the lugs carried by the extractors to move the upper portions of the extractors rearwardly and to re..- move the empty shell case from the gun in the usual manner. However, during the final portion of the openin movement of the breechblock the l6 received by grooves H8 in the breech ring, the

grooves and flanges bein inclined upwardly and forwardly so. that as the breechblock is moved upwardly to close the breech it moves slightly forward and forces the round into its seat.

Formed in the lower portion of the breechblock is a. T-shaped slot 22 (Fig. 2) which is inclined upwardly toward'the front face-of the block and receives blocks 24 carried by a pin 25 on the end of. an operating crank 26 carried by a crank shaft 28 journaled in. thelower portion of the breech ring just forwardly of the breechblock. Carried latches which hold the plates forming the rear walls of the cam slots are engaged by the extractor lugs whereupon springs carried by the lower portions of the plates. urgethe'lower portions forwardly and the upper portions rearwardby the outer end'of the crank shaft is a crank arm 30 (Fig.1).toiwhich is secured a chain 32 which extends rearwardly of the gun and is connected to a rod 34 carrying at its rearward end ly. This action does not take place until thebreechblock has descended sufficiently far for the lugsto clear the shoulders in the forward'walls:

whereupon the springs, acting'on the extractors move them into lockin positions. mentof: the, cam plates widens the upper portionsof the cam. slots so that during the loading operation and the rearward movement ofthe lugs off the shoulders they'will not engage the rearward: walls of. the cam. slots before the heavy spring,.acting on the breechblock, has time to initiate its upward movement. Thus there is nothing. to prevent the round from entering. the breechblock completely'and wear on the parts, due to'thev heavyv blow between the lugs and the rearward walls of the. cam slots, is eliminated.

With. this construction it is unnecessary toram the. rounds as hardiintothe gun as formerly. This also eliminatesthe need for crimping the projectile into, the shell case asmuch as is necessary with the usualconstruction necessitated by fast ramming, to prevent. the projectile from leaving theshellicase when the round comes to rest.

Theabove and other features ofthe invention,

including. variousnovel details of construction and combinations ofparts will now bemore particularly. described with reference to-the accompanying drawings and pointed out in the claims.

- Inthedrawings:

Fig.1: is a side elevation of. the breech end of V agun in which the present invention is embodied Fig.2 is a section on the line II-II of Fig.1;- Fig.3 is a detail View in side elevation of a portion of the gun carriage carrying the cam plate" This move by whichopening movement isimparted to the =breechblock duringicounter-recoil of the gum "Fig. 4 is a section on the lineIV-JV of Fig.- 3'; Fig; 5. is a, vertical longitudinal section through the-breech 'end'of the gun with the breechblockin open position and around being loaded'into the n;

Fig. 6 is a similar viewshowing the positions of theparts immediately after'the round 'is loaded in the gun but before thebreechblock has closed; I

s Fig. 7 is a view similar to'Figs. 5 and "6 but showing the parts in the positions assumed after thebreechblock is closed Fig. 8 is a detail view partly in section of thevv latchmechanism for holding the plate'formin'g" the rearward wall ofthe cam track'in operative position during opening movement of the breechblock, and

Fig. 9 is a section on the line IX-IX'Of Fig. .8.

The. invention isilIustrated as embodied in a During opening of the breechblock the extractors: 7.0;

gunlfll having a breech ring l2-provided with a vertically slidable breechblock Id. The, breechblock is provided in itsopposite side's withfianges;

a spring retainer 36 slidable in a cylinder 38. A heavy compression spring lfl acts between the spring-retainer 36 and shoulders formed in the forward end of the cylinder to urge the rod 34 rearwardly and turn the crank shaft 28 in a clockwise: direction as viewed in Figs. 1 and 5 to raise the breechblock. 'Means to be described holds the.

breechblock in the positionshown in Fig. 5, when the gun is not loaded, against the force. exerted by the spring Mlbut when this hOldiIlg" means is: released, rotation of thecrank-shaft 28 in a clock wise direction by the spring causes. the breech-- block to move. into the closed positionjshownin Fig.7.

After firing of the gun and at thebeginning of the counter-recoil movement the breechblockis. again opened. For this purpose the crank shaft 28 on itsleft end carries a crank 42- (Figs. 2;.3.

- and 4) provided with a camfollower M; Pivoted at'45 to the-gun carriage is a cam plate 46 normally urged inwardly-of the gun by a spring 48 into position to. be engaged by the camfollower- 44 during movements of the gun in recoil and. counter recoil. The forward face of the cam plate. 46-isinclinedat 50 (Fig. 4) so that during recoilv of the gun the cam follower 44 rides along the surface 50 urging. the cam plate 46 outwardly against the force of the spring 48,,withoutcausing any rotationofthe crank shaft 28. At. the

completion of the recoilmovement, thecam follower 44 passes. beyondthe end of the plate-46 whereupon the plate again assumes the-position shown in Fig. 4. During the counter-recoil move-' ment the cam follower engages a-cam surface EZ -(Fig. 3) formedalong the edge of the plate so that the crank 62 moves from the broken line position-shown in Fig. 3 into the full line position thus causing turning of the crank shaft 28- in a;

counterclockwise direction as viewed inFig. 5

so that the breechblock is moved downwardly into open position.

This downward movement of the breechblock causes the empty. shell case to be ejected from thegun. For this purpose a pair of extractors, 54 are provided, .these extractors. having outwardly extending "trunnions 56' (Fig. 2) I received in curved slots 58in the breech ring of the gun' at opposite; sides of the breechblock. The: upper" ends of. the extractors have inwardly extendinglips59 arranged for engagement by therim ofthe shell case. With the breechblock closed'the extractors assume the positions shown =inFig'. 7;

are rocked into the positions shown in Fig. 5 thus moving the shell case .-rearwardly,";theexi tractorsmoving sufficiently fast to cause the shell case'to be-completely. ejected from-the breecho-f. the. gun. Forqthusmovingjthes eXtractors,-inwardlyextendin'gg lugs;. 60 are? received; inicamf the upperends wise direction against experienced due to high velocity ramming,

is sufficiently wide the cam path spring 40 is grooves 62 formed in the sides of the breechblock, of the cam grooves extending forwardly. whereupon the extractors are rocked in a counterclockwise dlrection toward the end or the opening movement of the breechblock. The forward walls of the cam slots are slabbed off at their upper ends to form shoulders 64 upon which rest the lugs 50 carried by the extractors when the breechblock reaches the end of its downward movement. For thus moving the lugs onto the shoulders 64, spring-pressedplungers 68 are carriedby the walls of the breech ring at opposite sides of the breechblock. These springs also maintain the extractors 54 in locking positions relativelyto the breechblock as long as the gun remains unloaded. Upon loading the gun the rim of the shell case lips 59 on the extractors thus moving the extractors in a clockthe forces exerted by the spring-pressed plungers 68 whereupon the lugs t movement of the breechblock under the force exspring 4i) To eliminate enli with the rearward walls of of the parts commonly as outthe rearward walls of the cam slots 62 are formed of plates H1 pivoted at 12 to the breechblock and having curved upper end portions for completing the upper portion of the cam track when the plates are in the positions shown in Fig. 7. The plates are held in these positions when the breechblock is in closed position and until-the end of the erted by the heavy gagement of lugs 6 the cam slots and wearing the breechblock. The latches are normally urged into latching relationship with the upper ends of the plates 10 by spring-pressed plungers 18 (Fig. 8), the outer ends of which ride on surfaces til formed in the breechblock. The lower ends of the leaf springs 82 which act to move the plates toward the positions shown in Fig. 6 upon release of the latches 14. The latches are released by the trunnions 8 when the breechblock has moved downwardly sufficiently for the trunnions 60 to clear the shoulders 64. Accordingly, when the breechblock is locked in its opening po sition, the latches M have been released and the plates I0 assume the positions shown in Fig. 5. Upon ramming the round into the gun the extractors are rocked in a clockwise direction against the forces of the spring-pressed plungers 68 but at this time the upper end of the because the plates 10 so that the trunnions 68 do not move into engagement with the'rearward surfaces of with a heavy impact before the effective to raise the breechblock.

moves upwardly into closed of the plates 19, which in Figs. and 6, this time thus causing the tions they are locked by the latches Hi so that after firing of of the breec d movement of to eject the empty shell case from the end of this downward movement,

the latches 14 are again released and the parts resume the positions shown in Fig.

From the above it will be seen that by the use cam track opening movement thereof by latches l4 pivoted at 16 in recesses formed in a of the pivoted plates forming the rearward walls of the cam slots by which the extractors opened, the extractors are free to move the impact of a round during the loading opera-v tion to unlock the breechblock. The velocity of ramming may therefore be reduced and impact of the lugs 60 with the rearward walls of the cam slots is eliminated so that excessive wearing of the parts due thereto will be substantially reduced.

Having thus described my invention, what I claim as new and desire to secure by Letters Patent of the United States is: i i

1. For use in a gun oi the type havmg a breech ring and extractors carried by the breech ring having inwardly extending lugs, a able wedge-typebreechblock, vertical cam grooves in the sides or the breechblock having forwardly inclined upper portions arranged to receive the inwardly extending lugs of said extractors, the rearward walls of said cam grooves beingformed of movable plates, means acting on said plates in directions to widen the upper ends of the cam grooves, and latches for holding said plates in operative positions, said latches having portions arranged for engagement. by the inwardly extending lugs of theextractors for re leasing said latches to permit such movements of the plates.

2. In a gun or the type having a vertically slidable wedge-type breechblock, extractors or removing an empty shell case from the gun upon breechblock and for locking the cam grooves in the sides of the breechblock, and inwardly extending lugs carried by the extractors received in said cam grooves; that improvement which comprises movable plates forming the rearward wallsof said cam grooves, and means for moving the upper ends of the plates rearwardly toward inoperative positions to widen the upper portions of the cam grooves when the extractors move to their rearwardpositions in response to opening of the breechblock.

3. In a gun of the type having a vertically slidable wedge-type breechblock, extractors for removing an empty shell case from the gun upon opening Of'the breechblock and for locking the breechblock open, cam rooves in the sides or the breechblock, and inwardly extending lugs carried by the extractors received in said cam grooves; that improvement which comprises movable plates forming the rearward walls of said cam grooves, and means for moving the upper ends or the plates rearwardly toward inoperative positions to widen the upper portions extractors move to their rearward positions in response to opening of the breechblock, said plates having portions engageable by said lugs for moving the upper ends of the plates forwardly into operative positions during closing movement of the breechblock.

4. In a gun or the type having a vertically slidable wedge-type breechblock, extractors for removing an empty shell case from the gun upon opening or the breechblock and for locking the breechblock open, cam grooves in the sides or the breechblock, and inwardly extending lugs carried by the extractors received in said cam grooves; that improvement which comprises movable plates forming the rearward walls of said cam grooves, means ends or the plates rearwardly toward inoperative positions to widen the upper portions or the cam are , ems-,eze

grooveswhenth'e;extractorszmove to.-their;rear:- into closed; position-extractors carried; by the Ward:

,ositions in: response. toopening ofthe reech ring. forrocking; movements; said-extraqrbreechblock, torshaving, inwardly extending lugs}, said receive said lugs; saidcam: grooves.abeing-,-ar-

able wedge-type breechblock, extractors for re- 10 tions'I-of, thBafOIfWaTd I'W-aJIS-Of the-cam; grooves inoperative; positions with the upper portions of ment of the breechblock, said latches beingrboward said inoperative-positions. Y

6. In a gun 0f the type having a verti ally slidv able wedge-type breechblock, extractors, for reblock being provided with camflgrooves to recarried by the. extractors receiveci in said cam t y; breechbloc'k into OpenpOsm-on, upper in p ra ivep t ,with the'upi er portions f 40 ing the rearward .vvalls. of said cam grooves;

by theinwardly extending lugs-oftheextractors of. t extractor-sresponse to downward in. inoperative positions, with the inwardly ex- 1 into operative positions.

7. A breech mechanism comprising a breech ring having a vertically slidable breechblock, 5 means acting cnsaid block tomove. it upwardly I SIDNEY'J.

No. references. cited;

breechblock being; provided withcamgrooves to. 

